Metal-nitrogen-doped hybrid ionic/electronic conduction triple-phase interfaces for high-performance all-solid-state lithium-sulfur batteries

The point-to-point contact mechanism in all-solid-state Li-S batteries (ASSLSBs) is not as efficient as a liquid electrolyte which has superior mobility in the electrode, resulting in a slower reaction kinetics and inadequate ionic/electronic conduction network between the S (or Li2S), conductive carbon, and solid-state electrolytes (SSEs) for achieving a swift (dis)charge reaction. Herein, a series of hybrid ionic/electronic conduction triple-phase interfaces with transition metal and nitrogen co-doping were designed. The graphitic ordered mesoporous carbon frameworks (TM-N-OMCs; TM = Fe, Co, Ni, and Cu) serve as hosts for Li2S and Li6PS5Cl (LPSC) and provide abundant reaction sites on the triple interface. Results from both experimental and computational research display that the combination of Cu-N co-dopants can promote the Li-ion diffusion for rapid transformation of Li2S with adequate ionic (6.73 × 10−4 S·cm−1)/electronic conductivities (1.77 × 10−2 S·cm−1) at 25 °C. The as-acquired Li2S/Cu-N-OMC/LPSC electrode exhibits a high reversible capacity (1147.7 mAh·g−1) at 0.1 C, excellent capacity retention (99.5%) after 500 cycles at 0.5 C, and high areal capacity (7.08 mAh·cm−2).